I have someone in my memories /people list who is not related to me at all. She is not on my family tree so don't know how she got there and it seems I would have to delete her whole details page which belongs to her relatives. Any help appreciated.
go to the person profile - and the memories section for that person - and see if you inadvertantly uploaded an item to that persons memories tab.
anyone can upload a memory to any persons record - whether or not they are related or not.